MONROE, Conn. — On the most challenging back-to-school day in this region’s history, a little boy’s simple gesture comforted hundreds of worried parents and put an anxious nation at ease.

Looking out the window of a school bus that carried him to a new unknown, the boy, Liam O’Connell, in a sweater as red as Santa’s suit, raised his hands, separated the forefinger and middle finger of each to form a “V” — and expressed what his neighbors have been conveying for weeks.

“Peace.”

It’s OK, he was saying. We will be all right.

“I think it’s good for kids to be with other kids who’ve experienced the same thing, and be allowed to be kids,” said Erin Nikitchyuk, whose son Bear was in the hallway when the slaughter at Sandy Hook Elementary School in Newtown started.

Three weeks after the senseless massacre that killed 20 students and six staffers, students yesterday returned to a school with the same name in a different building in another town seven miles away.

Residents of neighboring Monroe embraced the brave little ones with welcome signs, ribbons and balloons, most in Sandy Hook’s green-and-white school colors that are now the colors of healing.

The last time young Freddy Hubbard saw a chalkboard, his little sister, Catherine, was murdered with a group of other pupils in a classroom down the hall.

Still, the fifth-grader couldn’t wait to get back to school again to see his teachers and swap stories with other fragile students.

“We’re so proud of him,” said his still-grieving mother, Jennifer Hubbard. “In some respects, he knows there’s not going to be a normal.”

Hubbard said she is aiming for something higher than normal. Normal is what made her son spend Christmas under the specter of a shooting. Normal is what stole his innocence and sparked questions a mother could not answer.

“I pray we don’t go back to normal,” Hubbard said before she laid out Freddy’s clothes and put him on a school bus. “Are we willing to say that normal is a place where first-graders, teachers and administrators being brutally killed is acceptable?”

The students made their new home in Monroe’s former Chalk Hill Middle School, which was refurbished with fresh paint and new furniture.

Workers even raised the bathroom floors so the smaller elementary-school students could reach the gleaming toilets.

Students’ desks, backpacks and other belongings left behind after the shooting were taken to the new school to make the youngsters feel more at home.

Patrol cars surrounded the school’s new home, and officers asked parents for identification when they dropped off their sons and daughters.

But the strict security measures were not enough for some worried parents.

“For us, it was not a great day,” said Christine Wilford, 35, whose second-grade son, Richie, 7, lost a close friend that awful day. She said her son began hearing gunshots in his head during the school day:

“He got on the bus just fine this morning. He’d said the last few days that he wanted to go back to school. He was excited to go back. Then he got there and is having a rough time. He just doesn’t want to be there.”

Len Pozner said he wasn’t taking the chance. Still mourning his 6-year-old son, Noah, he kept home Noah’s twin, Arielle, and 7-year-old sister, Sophia — who survived the attack paralyzed in fear as they hid in classrooms down the hall.

“I’m still in a light state of shock,” Pozner said.

“If you asked me what day of the week it is, I’d really have to think about it. If you had the National Guard at the school, we may have felt comfortable letting our kids return.”